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Objective: There are limited biomechanical data supporting the use of anterior or superior-lateral precontoured clavicle plates for the treatment of displaced Neer type II-A clavicle fractures. The objectives of this study were as follows: (a) compare noncontoured versus precontoured superior plating; (b) compare use of locking versus nonlocking screws in the lateral fragment for superior precontoured plates; and (c) compare superior versus anterior precontoured plates with locking lateral fragment screws. Methods: The following constructs were tested on a synthetic clavicle model simulating a Neer type II-A fracture: (a) superior precontoured plate with locking (SUP-L, n = 6); (b) superior precontoured plate with nonlocking (SUP-NL, n = 8); (c) anterior precontoured plate with locking (ANT-L, n = 7); and (d) superior noncontoured locking compression plate (SUP-LCP, n = 6). Constructs were subjected to cyclical cantilever loads. Construct stiffness and survival (cycles to failure) were documented. Mann–Whitney U tests were performed for group-wise statistical comparison (α = 0.05) of data. Results: The SUP-L construct was significantly stiffer than both SUP-LCP and ANT-L constructs (P < 0.02). The SUP-NL construct was stiffer than the SUP-L (P = 0.03) construct. Both SUP-L and ANT-L precontoured constructs survived longer than the noncontoured SUP-LCP construct (P < 0.022). The SUP-L construct survived longer than the SUP-NL (P = 0.013) and the ANT-L (P = 0.008) constructs. Conclusions: Superior precontoured plates yielded biomechanically superior constructs compared with anterior precontoured and superior noncontoured plates. Using locking screws in the lateral fragment over nonlocking screws may improve overall superior precontoured plate construct survivability. However, our results were limited to a synthetic biomechanical model and require further investigation to establish a clinical correlation.

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